1. Field of the Invention
Our invention is directed to designing and storing light shows to be used in light objects. Light objects include any object that is intended to provide light for illumination or decoration. Light objects, therefore, include projectors, light bulbs for conventional light sockets, internally lit sculptures, night lights, etc. Our invention is also directed to novel light shows for use in light objects. More specifically, our invention is directed to using various formulae and/or CIE (Commission Internationale de l'Eclairage) coordinates to define the colors to be used in a light show and the manner in which the colors change over the course of a light show.
2. Description of the Related Art
Home lighting effects have proven important and desirable to consumers seeking settings anywhere from soothing to dramatic. In particular, dimmers and specialized light shades have provided consumers with the ability to create warm and intimate settings. Neon light sculptures have enjoyed popularity in connection with adding color and a dramatic effect to one's home. Candles are still routinely used to create a pleasant ambience.
There are, of course, numerous other examples of lighting effects employed by individuals to create pleasing environments in their living spaces, including decorative light/illumination objects. U.S. Pat. No. 6,685,339 (directed to a sparkling light bulb), U.S. Pat. No. 6,459,919 (disclosing color controllable track lighting), and U.S. Pat. No. 5,924,784 (directed to simulated candles) describe various light objects that produce light shows for a user's viewing pleasure. Light objects include any object that is intended to provide light for illumination or decoration. Light objects, therefore, include projectors, light bulbs for conventional light sockets, internally lit sculptures, night lights, etc.
With advances in light emitting diodes (LEDs) and the growing availability of inexpensive lighting products using them, LEDs are becoming a popular way to produce aesthetically pleasing lighting effects. With substantially instantaneous activation and deactivation of the light emitted from LEDs, they provide more versatility than conventional lighting devices, which are relatively slow to reach their optimum brightness, and fade out when shut off (e.g., fluorescent and incandescent lights). This versatility in LED lighting devices has led to the use of LEDs to mimic flickering flames, as is discussed in U.S. Pat. No. 5,924,784. In addition, the variety of colors of LEDs available and the ability to mix easily the lights of different color LEDs have led to the use of colored LEDs in various home lighting devices. For instance, U.S. Pat. No. 6,801,003 discusses the use of LEDs in providing light shows in decorative illumination objects, room illumination, and the like.
In operation, a single LED emits light of a dominant wavelength, or a very narrow range of wavelengths. (For purposes of simplicity, we will refer to the dominant wavelength of an the LED. That term should be interpreted also to include a narrow range of wavelengths.) For instance, a blue LED will emit a dominant wavelength of light in the blue range of the color spectrum. This dominant wavelength is not substantially controllable for a given LED (although the dominant wavelength and intensity can drift slightly with temperature fluctuations, for instance). The intensity of the light, however, can be controlled for a given LED. For instance, LEDs can be controlled by altering the applied current so as to vary the intensity of the light of the LED's dominant wavelength. This can be achieved by a number of means; however, pulse width modulation (PWM) is preferred. Preferably, a microcontroller is used in the control process, with the microcontroller including control logic that receives instructions from a memory or an outside source regarding the operation of the LEDs. With PWM, the microcontroller sets a cycle for each of the LEDs, and within that cycle, controls the ON time and the OFF time of the LED, such that a constant current is supplied to the LED for a portion (or portions) of cycle (i.e., the pulse width(s) of the duty cycle). By altering the pulse width of the duty cycle, the LED is controlled to be on for a portion of the cycle, and off for the remainder of the cycle. Thus, the diode flickers on and off as the duty cycle is repeated over time. This flicker, however, occurs so rapidly that an observer perceives a constant light emission, with the intensity of the light becoming greater as the pulse width is increased. Thus, greater control can be achieved as compared to conventional lights, which cannot be turned on and off as rapidly due to the time it takes to reach full intensity (e.g., heat the filament in an incandescent bulb) and cease light emission (e.g., wait until the filament cools).
Consequently, in LED lighting, an observer will observe a color corresponding to the dominant wavelength for the LED, and the variation in the pulse width will have a dimming effect. This method of controlling LEDs is known in the art, and thus will not be discussed in more detail. Other methods of operating LEDs are also known, and the use thereof would be obvious to one of ordinary skill in the art.
When different-colored LEDs are used together, the lights of the individual LEDs can be mixed together. For instance, U.S. Pat. No. 6,801,003 discusses a system in which the wavelengths of light from different-colored LEDs are combined. The mixture can be achieved by shining the lights on the same surface, placing the LEDs in close proximity to each other, shining the light from the LEDs through a diffuser, transmitting the lights through optical devices, and the like. When the lights of the different wavelengths are effectively mixed, an observer perceives the received mixture of wavelengths as a single color. The perceived color can then be altered by adjusting the respective intensities (e.g., duty cycles) of the different LEDs. This allows for color changing effects in the perceived light.
Even though the perceived color is varied by adjusting the relative intensities of the LEDs, each LED still only emits light of its dominant wavelength. Consequently, the specific wavelengths of light used to create the lighting effects are not indicative of the color changes perceived by an observer.
The perceived color, however, may be defined in accordance with a standard known as the Commission Internationale de l'Eclairage (CIE) classification. The CIE classification is provided in the form of a color chart, which is shown in FIG. 1, although shown in black and white here. Representations of the actual colors in the chart can readily be obtained from available sources such as “Color Vision and Colorimetry: Theory and Applications,” by Daniel Malacara (SPIE Press 2002).
A single LED, emitting a dominant wavelength, provides a perceived color represented by one point (i.e., one set of coordinates) on the CIE chart. Consequently, two different color LEDs can be represented by two different points on the CIE chart. When those two LEDs are operated together to combine their emitted wavelengths of light, the perceived light obtainable by varying the relative intensities of the two LEDs is defined by a line on the CIE chart connecting the two points.
It is generally known in the art that LEDs can be used in combination to obtain different colored lights, as defined on a CIE chart. For instance, U.S. Pat. No. 6,498,440 discusses the dynamics of obtaining differently perceived light colors along a line connecting two points on a CIE chart corresponding to two specific LEDs. U.S. Pat. No. 6,411,046 describes the combination of the light emission of multiple LEDs of different colors, which LEDs are controlled to maintain a consistent white light (as defined on a CIE chart) under various ambient conditions.
By varying the relative intensities of combined light from two or more LEDs, the LEDs can operate to produce a wide array of differently-perceived colors.
With all of these advancements, however, there remains room for improvement in the art of LED operation and light show design and implementation.
In particular, in conventional illumination objects in which LEDs are implemented to display a light show in which the perceived light color changes over time (for instance, a color wash), a microcontroller is typically connected to a memory which stores instructions for the operation of the LEDs during the course of the show. Specifically, a look-up table is conventionally used to store data indicating the respective LED settings for each point during the course of the show. Thus, for each point (i.e., new setting at a given moment in time) in the show, the look-up table includes data for the specific pulse width setting for each different LED used in producing the light show. Thus, over the course of the show, the LED settings are changed per specified unit of time. These different color points are provided one after the other to provide a color wash that appears to flow seamlessly from one color (i.e., point) to the next over the course of the show. Of course, the distance between the color points used will affect the perceived speed and the seamlessness of the show. This can lead to a relatively large amount of data, particularly if multiple light shows are to be stored in the memory and the device is a simple device for which the cost of memory chips is a significant portion of the manufacturing cost. Also, if a modular, replaceable memory card is to be used in a lighting device, as is a preferred improvement in our invention, the size of the memory is the primary cost of the unit (i.e., memory card) to be manufactured and sold.
We have overcome this shortcoming of conventional systems by developing a novel method of defining and storing data concerning the operation of a light show, which requires less memory than the conventional method of defining and storing data for every color point in the show, and is easier to design and program.
In addition, while the relationship between a CIE chart and particular LEDs is known in the art, we have improved on the art by developing novel light shows which we believe will be desirable to an observer, and defining those light shows with respect to a specified area on the CIE chart obtainable through the combination of a set of colored LEDs.